network: prevent SIGPIPE on OSX

OSX does not know MSG_NOSIGNAL. BSD (which OSX is based on) has got
the socket option SO_NOSIGPIPE (even if modern BSDs also support
MSG_NOSIGNAL).
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/network.c

@@ -153,6 +153,10 @@ int ff_socket(int af, int type, int proto)
             fcntl(fd, F_SETFD, FD_CLOEXEC);
 #endif
     }
+#ifdef SO_NOSIGPIPE
+    if (fd != -1)
+        setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &(int){1}, sizeof(int));
+#endif
     return fd;
 }